<!doctype html>
<html>
<head>
<meta charset=utf-8>
<script>
Element.prototype.animate = function() {
  throw 'Called animate() as defined in content document';
}
// Bug 1211783: Use KeyframeEffect (not KeyframeEffectReadOnly) here
for (var obj of [KeyframeEffectReadOnly, Animation]) {
  obj = function() {
    throw 'Called overridden ' + String(obj) + ' constructor';
  };
}
</script>
<body>
<div id="target"></div>
</body>
</html>
